President Barack Obama says enacting stricter gun laws "will be difficult" but is necessary following the Newtown massacre.

"The world has changed and it's demanding action," Vice President Joe Biden said, acknowledging the political challenges ahead. Mr Biden had been tasked with bringing recommendations to the president.

The president said in a news conference on Wednesday he will sign 23 executive actions, but said they are not a substitute for action in Congress.

As part of his $500m (£311m) plan, he called on federal lawmakers to pass several proposals "right away", including universal background checks for anyone trying to buy a gun.

Right now, some 40% of US gun purchases are made without background checks.

Mr Obama also asked Congress to restore the expired ban on military-style assault weapons and to enact a 10-bullet limit on high-capacity ammunition magazines.

And he said Congress has to "help rather than hinder" law enforcement efforts on gun safety, calling on lawmakers to confirm his nominee for the next Alcohol, Tobacco and Firearms director, Todd Jones.

Vice President Biden had been tasked with surveying various gun interests

"If there is even one life that can be saved, then we've got an obligation to try. And I'm here to do my part", the president said.

He called on constituents in parts of the country that are traditional gun ownership strongholds - specifically "responsible gun owners" - to make their support for stronger controls known so "the usual suspects" do not solely dominate the debate.

Video:Congress 'Must Aprove Gun Controls'

The announcement promises to set up a bitter fight with a powerful pro-gun lobby that has long warned supporters that Mr Obama wants to take away their guns. The US has the highest rate of gun ownership of any country in the world.

"This is the land of the free and the home of the brave and always will be", Mr Obama said, acknowledging the Constitution's Second Amendment right to bear arms. "But with rights, come responsibilities".

"We live in a society. A government of, for and by the people. We are responsible for each other."

The fundamental rights to life and liberty have been denied to the victims of gun violence, he said.

He added: "Those rights are at stake. We're responsible."

Following his speech the president signed some of the executive actions that do not need Congressional approval. They are reported to include measures to stiffen enforcement of existing laws and launching a national responsible gun ownership campaign.

The move comes just over a month after the massacre at Sandy Hook Elementary School in Newtown, Connecticut, that took the lives of 20 young children and six school employees.

Mr Obama said 900 Americans had been killed by gun violence in the month since that deadly shooting.

In response to Wednesday's announcement, the National Rifle Association issued a statement saying, "attacking firearms and ignoring children is not a solution".

"Only honest, law-abiding gun owners will be affected and our children will remain vulnerable to the inevitability of more tragedy," the statement said.

Meanwhile, chairman of the Senate Judiciary Committee said on Wednesday he will begin hearings in two weeks on gun safety proposals.

Democratic Senator Patrick Leahy of Vermont – a gun owner – said he wants to hold a series of hearings examining violence in popular media and how to keep guns safe, among other topics.

His plan could lead to a slower process in Congress than gun control advocates would like.